This proposal consists of six projects which relate to the structure and function of the gastrointestinal tract and to the pathogenesis of its disease. The following will be studied: I. Production of intestinal particles during linolenate absorption in man, II. Influence of Mg ions and of Ca ions on intestinal water absorption, III. Effect of palmitic acid on the route of transport of other fatty acids from the intestine, IV. The apoproteins of human intestinal absorptive cells: An immuno-morphological analysis, V. The structure and function of the gastrointestinal tract in disorders of propulsion, VI. Rectal biopsy studies in inflammatory bowel disease.